Samsung LT20A350 Service Manual page 33

4. Troubleshooting
4-1-3. No Video (Analog PC signal)
Symptom
- Audio is normal but no picture is displayed on the screen.
- Check the PC source
Major
- Check the Arsenal, Check the Main Chipset.
checkpoints
- This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.
Diagnostics
1
2
Caution Make sure to disconnect the power before working on the IP board.
4-4
SMPS BOARD
Power indicator LED is off.
Lamp(Backlight) on, no video ?
Yes
Check the PC source and
check the connection of D-SUB ?
Yes
Does the signal appear at
PIN - R, G, B, HS, VS (R, G, B, H, V) ?
Yes
Does the digital data appear at
TP-E_TXCLK+, E_TXCLK- ?
Yes
Check the LVDS cable?
Check the T-Con B'd?
Replace the LCD panel?
MAIN BOARD
No
Check a set in the 'Stand-by mode'
or 'DPMS mode'
No
Input the analog PC signal properly.
No
Check CN401, PC cable.
Change the Main Assy.
No
Check IC1111 (X5).
Change the Main Assy.
No
Please, Contact Tech support.